Interlaboratory discrepancy of antigenuria results in 2 patients with AIDS and histoplasmosis

Histoplasma polysaccharide antigen testing is used routinely to diagnose histoplasmosis. At least 3 antigen tests are commercially available. Controversy exists about the relative accuracy of these tests. We report 2 patients with AIDS and culture-confirmed Histoplasma capsulatum meningitis from whom discrepant Histoplasma polysaccharide antigen results were obtained from different laboratories and discuss the potential clinical implications of these results.